Question

I have been working with regular expressions for the past couple days in class. I cannot determine why this expression doesn’t work. I am looking for expressions like the following:

value = (struct node){ 5, NULL};
value2 = (structname){ 1, 2 }; 
*pointer = ( bla ){3,4};

Here is the expression I am using:

sed -n '/^[*0-9A-Za-z_]+ *= *( *[0-9A-Za-z_]+ *[0-9A-Za-z_]* *) *{[0-9A-Za-z, ]};/p'     structfile

What am I missing because it returns nothing. Also a side note I have used [^,] in some expressions and I still get lines with , s. What am I missing?

Answer 1

You need to escape +; and fix {[0-9A-Za-z, ]} to {[0-9A-Za-z, ]*}.

sed -n '/^[*0-9A-Za-z_]\+ *= *( *[0-9A-Za-z_]\+ *[0-9A-Za-z_]* *) *{[0-9A-Za-z, ]*};/p' structfile


me@localhost:~$ cat structfile 
value = (struct node){ 5, NULL};
value2 = (structname){ 1, 2 }; 
*pointer = ( bla ){3,4};
not astruct
notastructstr =

me@localhost:~$ sed -n '/^[*0-9A-Za-z_]\+ *= *( *[0-9A-Za-z_]\+ *[0-9A-Za-z_]* *) *{[0-9A-Za-z, ]*};/p' structfile
value = (struct node){ 5, NULL};
value2 = (structname){ 1, 2 }; 
*pointer = ( bla ){3,4};